QProperty: Only try to avoid TLS access if currentThreadId is faster

We will not gain anything if we have to do multiple function calls to
obtain the thread id. Therefore we introduce a macro to signal that we
have a fast implementation of currentThreadId, and only use the function
if it is defined.

Change-Id: I3347489ea91992896bb753b796ae26e391c2c99c
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
(cherry picked from commit 5889985c8c8e8cc676de4480ad95979287860b96)

1 files changed, 9 insertions, 1 deletions

diff --git a/src/corelib/kernel/qproperty.cpp b/src/corelib/kernel/qproperty.cpp
index 82ab3b9b59..3123858d83 100644
--- a/src/corelib/kernel/qproperty.cpp
+++ b/src/corelib/kernel/qproperty.cpp
@@ -523,8 +523,12 @@ void QPropertyBindingData::notifyObservers(QUntypedPropertyData *propertyDataPtr
     if (QPropertyObserverPointer observer = d.firstObserver()) {
         auto status = storage ? storage->bindingStatus : nullptr;
         QPropertyDelayedNotifications *delay;
+#ifndef QT_HAS_FAST_CURRENT_THREAD_ID
+        status = &bindingStatus;
+#else
         if (!status || status->threadId != QThread::currentThreadId())
             status = &bindingStatus;
+#endif
         delay = status->groupUpdateData;
         if (delay) {
             delay->addProperty(this, propertyDataPtr);
@@ -2171,12 +2175,16 @@ void QBindingStorage::registerDependency_helper(const QUntypedPropertyData *data
     Q_ASSERT(bindingStatus);
     // Use ::bindingStatus to get the binding from TLS. This is required, so that reads from
     // another thread do not register as dependencies
-    const bool threadMatches = (QThread::currentThreadId() == bindingStatus->threadId);
     QtPrivate::BindingEvaluationState *currentBinding;
+#ifdef QT_HAS_FAST_CURRENT_THREAD_ID
+    const bool threadMatches = (QThread::currentThreadId() == bindingStatus->threadId);
     if (Q_LIKELY(threadMatches))
         currentBinding = bindingStatus->currentlyEvaluatingBinding;
     else
         currentBinding = QT_PREPEND_NAMESPACE(bindingStatus).currentlyEvaluatingBinding;
+#else
+    currentBinding = QT_PREPEND_NAMESPACE(bindingStatus).currentlyEvaluatingBinding;
+#endif
     QUntypedPropertyData *dd = const_cast<QUntypedPropertyData *>(data);
     if (!currentBinding)
         return;